JP2018137859A - Vibration wave motor and optical device including vibration wave motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compact linear-motion vibration wave motor having a small thickness with respect to the pressurization direction for pressing a vibrator.SOLUTION: A vibration wave motor 100 comprises: a vibrator 103 including a piezoelectric element 101 and a vibration plate 102; a friction member 104 having a friction contact surface 104c which comes into contact with the vibrator 103; pressurizing means for pressing the vibrator 103 against the friction member 104; and guide means for guiding relative moving of the vibrator 103 and the friction member 104, wherein vibration generated by the vibrator 103 causes relative moving of the vibrator 103 and the friction member 104. The guide means holds the friction member 104 in a rotatable manner with respect to the vibrator 103.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a vibration wave motor, in particular, a linear motion vibration wave motor and an optical apparatus such as a lens barrel having the vibration wave motor.

  In a conventional direct acting ultrasonic motor, a vibrator to which a piezoelectric element is fixed is vibrated by applying a high frequency voltage to the piezoelectric element. The friction member pressed by the vibrator is driven by the vibration of the vibrator. The direct acting ultrasonic motor has high driving efficiency, and various devices for reducing the size while maintaining high output are considered.

  For example, the direct acting ultrasonic motor of Patent Document 1 guides the movement of the holding member, a vibrator having a piezoelectric element, a friction member to which the vibrator is pressed, a holding member that holds and moves the vibrator, and the like. The guide portion and the pressure member that presses the vibrator against the friction member are configured.

Japanese Patent Laying-Open No. 2015-220911

  However, the direct acting ultrasonic motor disclosed in Patent Document 1 is composed of individual parts such as a friction member, a vibrator, a holding member, a pressure member, and a guide part, and thus has a large number of parts. Furthermore, since the individual parts are stacked in the pressing direction for pressing the vibrator, there is a limit to reducing the thickness in the pressing direction.

  Accordingly, an object of the present invention is to provide a compact direct-acting vibration wave motor that realizes a reduction in thickness in a pressing direction in which a vibrator is pressed.

  In order to achieve the above object, the present invention provides a vibrator comprising a piezoelectric element and a diaphragm, a friction member having a friction contact surface in contact with the vibrator, and a pressurizing means for pressing the vibrator against the friction member. And a guide means for guiding relative movement between the vibrator and the friction member, and in the vibration wave motor for moving the vibrator and the friction member relative to each other by vibration generated in the vibrator, the guide means vibrates the friction member. It hold | maintains so that rotation with respect to a child is possible.

  ADVANTAGE OF THE INVENTION According to this invention, the compact direct acting type | mold ultrasonic motor which implement | achieved thickness reduction with respect to the pressurization direction which presses a vibrator | oscillator can be obtained.

1 is a front view of a vibration wave motor 100 according to the present invention. (A) It is sectional drawing of the vibration wave motor 100 by this invention. (B) It is sectional drawing of the conventional linear motion type ultrasonic motor 200. FIG. It is sectional drawing of the vibration wave motor 100 by this invention, and shows the load by applied pressure. (A), (B) It is sectional drawing of the vibration wave motor 100 by this invention, and the behavior of each member when the friction member 104 inclines in the Z-axis direction centering on the rolling member 107b is shown. (A) It is a front view of the vibration wave motor 100 by this invention. (B), (C) It is sectional drawing of the vibration wave motor 100 by this invention, and is sectional drawing which shows the behavior of each member when the friction member 104 inclines to the X-axis direction centering on the rolling member 107b. 1 is a cross-sectional view of a lens barrel 20 and a camera body 10 equipped with a vibration wave motor 100 according to the present invention.

(Example)
Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same reference numerals indicate the same members. In this specification, a direction in which a vibrator 103 to be described later and a friction member 104 to be described later move relative to each other is an X-axis direction, and a pressure direction in which the vibrator 103 is pressed against the friction member 104 is a Z-axis direction. In the Z-axis direction, the direction from the vibrator 103 to the friction member 104 is defined as the −Z-axis direction, and the direction from the friction member 104 to the vibrator 103 is defined as the + Z-axis direction. A direction orthogonal to the X-axis direction and the Z-axis direction is taken as a Y-axis direction. In the following description, a direct-acting vibration wave motor unitized as an actuator for driving a lens barrel of a digital camera will be described as an example. However, the usage of the present invention is not limited to this.

  FIG. 1 is a front view of a direct-acting vibration wave motor (hereinafter referred to as “vibration wave motor 100”) according to an embodiment of the present invention. 2A is a cross-sectional view of the vibration wave motor 100 taken along a cross-sectional line IIA-IIA in FIG. 1, and FIG. 2B is a cross-sectional view of a conventional direct acting ultrasonic motor 200. The vibration wave motor 100 according to the present embodiment has a long axis in the X-axis direction and is configured by members described below.

  With reference to FIG. 1 and FIG. 2 (A), the structure of the vibration wave motor 100 in a present Example is demonstrated. The vibrator 103 includes a diaphragm 102 and a piezoelectric element 101. The piezoelectric element 101 is fixed to the diaphragm 102 with a known adhesive or the like, but the method of bonding the diaphragm 102 and the piezoelectric element 101 is not limited as long as they are bonded. The vibration plate 102 further includes a friction contact portion 102a on the surface opposite to the surface on which the piezoelectric element 101 is fixed, and the friction contact portion 102a is in contact with the friction member 104 in a pressure contact state accompanied by pressing. By applying a high-frequency voltage to the piezoelectric element 101, vibrations with a frequency in the ultrasonic region (ultrasonic vibration) are excited.

  When ultrasonic vibration is generated in the piezoelectric element 101, a resonance phenomenon occurs in the vibrator 103 constituted by the vibration plate 102 and the piezoelectric element 101. As a result, an elliptical motion occurs in the frictional contact portion 102a of the diaphragm 102. By changing the frequency and phase of the high-frequency voltage applied to the piezoelectric element 101, a desired motion can be obtained by appropriately changing the rotational direction and ellipticity ratio of the elliptical motion. The vibrator 103 is fixed to the relative drive member 108 by a vibrator support member 109 so as not to hinder the resonance phenomenon.

  The friction member 104 has a friction contact surface 104c that contacts the friction contact portion 102a of the diaphragm 102 parallel to the X-axis direction. The friction member 104 is supported by the relative drive member 108 via the two rolling members 107a and the one rolling member 107b, and is biased by the spring 105, so that the friction contact portion 102a and the friction contact surface 104c. The pressure contact state is maintained. The spring 105 corresponds to the pressurizing means in the claims.

  Furthermore, the friction member 104 has two side surfaces and a bottom surface, and one side surface is a sloped portion 104a that is a plane having a different angle around the X axis with respect to the friction contact surface 104c of the friction member 104 parallel to the X axis direction. Is provided, and a side groove 104b is provided on the other side surface. Two rolling members 107a are engaged with the inclined surface portion 104a, and one rolling member 107b is engaged with the side surface groove portion 104b.

  The relative drive member 108 has two grooves 108a parallel to the X-axis direction with which the two rolling members 107a are engaged, and a groove 108b parallel to the X-axis direction with which the rolling members 107b are engaged. The two groove portions 108a are provided in the arm portion 108c of the relative drive member 108, and the groove portion 108b is provided in the side wall portion 108d that substantially faces the arm portion 108c. The arm portion 108c is rotatably held by the shaft 110, and a biasing force is applied to the rolling member 107a and the rolling member 107b by generating a moment around the shaft 110 by the spring 105.

  That is, the two rolling members 107 a are sandwiched between the inclined surface portion 104 a of the friction member 104 and the two groove portions 108 a provided on the arm portion 108 c of the relative driving member 108. One rolling member 107b is held between the side surface groove portion 104b of the friction member 104 and the groove portion 108b provided in the side wall portion 108d of the relative drive member 108. With such a configuration, the two rolling members 107 a and the one rolling member 107 b receive the urging force of the spring 105 by the arm portion 108 c of the relative driving member 108 and roll while being driven by the driving force of the vibrator 103. Move in the X-axis direction.

  Further, the friction member 104 is rotatably held around one rolling member 107 b, and the rolling member 107 b is positioned in the pressurizing direction by the spring 105. The guide mechanism 106a is configured by any one of the two rolling members 107a, the inclined surface portion 104a of the friction member 104, the groove portion 108a of the relative drive member 108, or a combination thereof. The guide mechanism 106a guides the relative movement between the vibrator 103 and the friction member 104 in a straight line, and corresponds to the guide means in the claims. Similarly, the guide mechanism 106b is configured by any one or a combination of the rolling member 107b, the side surface groove portion 104b of the friction member 104, the groove portion 108b of the relative drive member 108. The guide mechanism 106b guides the relative movement between the vibrator 103 and the friction member 104 in a straight line, and corresponds to the guide means in the claims.

  Each member described above is incorporated and unitized as the vibration wave motor 100. In this embodiment, the inclined surface portion 104a of the friction member 104 is a flat surface, and the groove portion 108a of the relative drive member 108 is a groove shape. However, a configuration in which the flat surface and the groove shape are interchanged is also possible. Further, the groove 108b of the relative drive member 108 and the side surface groove 104b of the friction member 104 only have to be able to hold the rolling member 107b in a rollable manner, and can take various groove shapes.

  Next, the size of the vibration wave motor 100 of the present invention and the conventional direct acting ultrasonic motor 200 in the Z-axis direction will be described with reference to FIGS. 2 (A) and 2 (B). FIG. 2B is a cross-sectional view of a conventional direct acting ultrasonic motor 200. As constituent members in the Z-axis direction, a fixing member 211, a friction member 204, a vibrator 203, a vibrator support member 209, and a spring support. A member 212, a spring 205, a rolling member 207, and a guide 206 are arranged.

  In the conventional direct acting ultrasonic motor 200, the pressing direction of the spring 205 is the Z-axis direction, and the rolling member 207 receives the applied pressure by the groove 208 a of the relative driving member 208 and the guide 206. It must be clamped in the axial direction. On the other hand, in the vibration wave motor 100 of the present invention, as shown in FIG. 2A, a spring 105, a friction member 104, a vibrator 103, a vibrator support member 109, and a relative drive member 108 are used as constituent members in the Z-axis direction. It is arranged. However, the spring 105 is disposed with the generation direction of the biasing force of the spring 105 as the Y-axis direction, and the guide mechanism 106a, the guide mechanism 106b, and the friction member 104 can be arranged in parallel in the Y-axis direction. As described above, the vibration wave motor 100 according to the present invention can be reduced in thickness in the pressing direction because the thickness of the constituent members laminated in the Z-axis direction is smaller than that of the conventional direct acting ultrasonic motor 200. Further, since the guide means, the pressurizing means, and the member equalizing mechanism can be realized in an integrated configuration, the vibration wave motor 100 of the present invention has excellent effects such as downsizing and reduction in the number of parts.

  Next, with reference to FIG. 3, the force which acts on the structural member of the vibration wave motor 100 of this invention is demonstrated. FIG. 3 is a cross-sectional view of the vibration wave motor 100 of the present invention similar to FIG. When the load F1 is biased by the spring 105 to the arm portion 108c of the relative drive member 108, the load F1 is decomposed into a tangential force F1a and a normal force F1b of the rotation trajectory of the arm portion 108c around the shaft 110. can do. The tangential force F1a generates a moment M1 about the axis 110 in the arm portion 108c.

  The rolling member 107a is in contact with the arm portion 108c, and a load F2 is applied to the rolling member 107a by a moment M1. The slope portion 104a of the friction member 104 is in contact with the rolling member 107a, and a similar load F2 is applied to the slope portion 104a. The load F2 can be decomposed into a tangential force F2a and a normal force F2b of the rotation track of the friction member 104 around the rolling member 107b. The tangential force F2a causes the friction member 104 to generate a moment M2 about the rolling member 107b.

  The friction contact portion 102a of the vibration plate 102 is in contact with the friction contact surface 104c of the friction member 104, and a load F3 is applied to the friction contact portion 102a of the vibration plate 102 by a moment M2. This load F3 is a pressing force that presses the vibrator 103 against the friction member 104.

  Next, with reference to FIGS. 4A and 4B and FIGS. 5A to 5C, each of the friction members 104 in the vibration wave motor 100 of the present invention is tilted with respect to the diaphragm 102. The behavior of the member will be described. 4A and 4B are both cross-sectional views similar to FIG. 2A, and the friction contact surface 104c of the friction member 104 is in contact with the diaphragm 102 due to the shape error and clearance of each component member. The behavior of each member when changed in the Z-axis direction from the position shown in FIG.

  FIG. 4A shows a case where the friction member 104 is changed in the + Z-axis direction from the position shown in FIG. 2A (the position of the friction member 104 shown by a broken line in the drawing). Since the friction member 104 changes in the + Z axis direction, the arm portion 108c rotates from the position indicated by the broken line in the R2 direction around the axis 110 by the tangential force F1a shown in FIG. On the other hand, the friction member 104 receives the load F2 via the rolling member 107a and the slope portion 104a, and rotates in the R1 direction around the rolling member 107b by the tangential force F2a shown in FIG. Press.

  FIG. 4B shows a case where the friction member 104 changes in the −Z-axis direction from the position shown in FIG. 2A (the position of the friction member 104 shown by a broken line in the drawing). Since the friction member 104 changes in the −Z-axis direction, the friction member 104 rotates in the R3 direction around the rolling member 107b by the reaction force F3 ′ of the pressing force (load F3) with the vibrator 103. . On the other hand, the arm portion 108c receives a reaction force F2 'of the load F2 through the slope portion 104a and the rolling member 107a, and rotates from the position indicated by the broken line in the R4 direction around the shaft 110 by the reaction force F2'. As a result, the pressure contact state between the friction contact portion 102a and the friction contact surface 104c is maintained.

  5A to 5C show the behavior of each member when the distance between the diaphragm 102 and the friction member 104 changes depending on the position in the X-axis direction. 5A is a front view of the vibration wave motor 100, FIG. 5B is a cross-sectional view taken along a cross-sectional line VB-VB in FIG. 5A, and FIG. 5C is FIG. It is sectional drawing in the sectional line VC-VC. Friction member 104 and arm when friction contact surface 104c of friction member 104 is displaced in the -Z-axis direction on the + X-axis side and in the + Z-axis direction on the -X-axis side due to shape error or clearance of each component member Consider the behavior of 108c.

  In FIG. 5B showing the state on the −X axis side, when the friction contact surface 104c is displaced in the + Z axis direction on the −X axis side, the friction member 104 is caused by the reaction force F3 ′ of the load F3 shown in FIG. It is pressed by the vibrator 103 and rotates in the R5 direction around the rolling member 107b. The arm portion 108c is pressed against the friction member 104 rotated in the R5 direction by the reaction force F2 'of the load F2 shown in FIG. 3, and rotates in the R6 direction about the shaft 110.

  On the other hand, in FIG. 5C showing the state on the + X-axis side, when the friction contact surface 104c is displaced in the −Z-axis direction on the + X-axis side, the friction member 104 is rotated by the tangential force F2a shown in FIG. It rotates in the R5 direction around the moving member 107b. The arm portion 108c rotates in the R7 direction around the shaft 110, presses the friction member 104, and presses the vibrator 103.

  As described above, in the vibration wave motor 100 of the present invention, the guide mechanism 106a and the guide mechanism 106b can linearly guide in the X-axis direction and the member equalizing mechanism can be realized in an integrated configuration. Stable frictional contact of the frictional contact surface 104c is realized.

  FIG. 6 shows a lens barrel 20 as an example of a lens apparatus in which the vibration wave motor 100 of the present invention is incorporated. Since the lens barrel 20 is substantially rotationally symmetric, only the upper half is shown.

  A lens barrel 20 is detachably attached to a camera body 10 as an imaging device, and an imaging element 1 a is provided in the camera body 10. The mount 11 of the camera body 10 is provided with a bayonet portion for attaching the lens barrel 20 to the camera body 10. The lens barrel 20 has a fixed cylinder 21, and the fixed cylinder 21 is in contact with the flange portion of the mount 11. The fixed cylinder 21 and the mount 11 are fixed to screws (not shown). Further, the front barrel 22 holding the lens G1 and the rear barrel 23 holding the lens G3 are fixed to the fixed barrel 21. The lens barrel 20 further includes a focus lens holding frame 25 and holds the focus lens G2. The focus lens holding frame 25 is further held by a guide bar 26 held by the front lens barrel 22 and the rear lens barrel 23 so as to be linearly movable. The friction member 104 of the vibration wave motor 100 is formed with a fixing portion (not shown) and is fixed to the rear barrel 23 with a screw or the like.

  When the movable part including the relative drive member 108 of the vibration wave motor 100 is driven with the above configuration, the drive force of the vibration wave motor 100 is transmitted to the focus lens holding frame 25 via the relative drive member 108. The The focus lens holding frame 25 moves linearly while being guided by the guide bar 26.

  With the configuration as described above, it is possible to obtain a small vibration wave motor 100 that is thinned in the pressurizing direction, and it is possible to obtain an optical device on which the thinned vibration wave motor 100 is mounted. The present invention is not limited to the above embodiments, and can take any form as long as it is within the scope of the claims.

DESCRIPTION OF SYMBOLS 100 Vibration wave motor 101 Piezoelectric element 102 Diaphragm 103 Vibrator 104 Friction member 104a Slope part (guide means)
104b Groove (guide means)
104c Friction contact surface 105 Spring (pressurizing means)
106a, b Guide mechanism (guide means)
107a, b Rolling member (guide means)

Claims (10)

A vibrator comprising a piezoelectric element and a diaphragm;
A friction member having a friction contact surface in contact with the vibrator;
Pressurizing means for pressing the vibrator against the friction member;
A guide means for guiding relative movement between the vibrator and the friction member;
In a vibration wave motor that relatively moves the vibrator and the friction member by vibration generated by the vibrator,
The vibration wave motor characterized in that the guide means holds the friction member rotatably with respect to the vibrator.   The vibration wave motor according to claim 1, wherein the guide means performs a straight guide for the relative movement.   3. The vibration wave motor according to claim 1, wherein the guide unit is configured by a rolling member that supports the friction member, and transmits the pressure applied from the pressurizing unit.   The guide means further includes an inclined surface portion that engages with the rolling member on the friction member, and the inclined surface portion is parallel to the direction of the relative movement and has an angle different from the friction contact surface of the friction member. The vibration wave motor according to claim 3, wherein:   The said guide means is further provided in the said friction member, and is comprised, and the said groove part with which the said rolling member engages is comprised, The said groove part is parallel to the direction of the said relative movement, The Claim 3 or 4 characterized by the above-mentioned. Vibration wave motor.   The said rolling member is clamped by the said groove part of the said friction member by the said pressurization means, The said friction member is hold | maintained so that rotation is possible centering | focusing on the said rolling member. The described vibration wave motor.   The vibration wave motor according to claim 5 or 6, wherein one of the rolling members is sandwiched between the groove portions of the friction member and positioned in the pressurizing direction by the pressurizing unit.   The vibration wave motor according to any one of claims 1 to 7, wherein the pressurizing unit is arranged in a direction orthogonal to the direction of the pressing and the direction of the relative movement.   The vibration wave motor according to any one of claims 1 to 8, wherein the vibration wave motor is an ultrasonic motor using vibration of a frequency in an ultrasonic region.   An optical device having the vibration wave motor according to claim 1.

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